Ownership Profile

Top Holders

Holder Shares Held % O/S Share Change Filing Date
Fidelity Management & Research Company 18,801,882 14.98 91,157 3/31/18
Biogen Idec Inc 11,501,153 9.16 11,501,153 6/5/18
ClearBridge Investments, LLC 10,920,109 8.70 -64,709 3/31/18
The Vanguard Group, Inc. 10,375,396 8.27 269,184 3/31/18
Wellington Management Company, LLP 9,953,942 7.93 -943,091 3/31/18
Bellevue Asset Management AG 8,828,520 7.03 435,480 3/31/18
BlackRock Institutional Trust Company, N.A. 6,592,605 5.25 -37,859 3/31/18
Baillie Gifford & Co. 6,262,651 4.99 -349,650 3/31/18
Waddell & Reed Investment Management Company 4,530,100 3.61 -- 3/31/18
State Street Global Advisors (US) 2,965,247 2.36 212,705 3/31/18

Top Holders: Mutual Funds

Fund Shares Held % O/S Share Change Filing Date
Fidelity Growth Company Fund 7,384,094 5.88 -7,686 4/30/18
Ivy Science and Technology Fund 4,180,000 3.33 1,965,100 3/31/18
Vanguard Total Stock Market Index Fund 3,121,904 2.49 40,052 5/31/18
Vanguard Small-Cap Index Fund 3,027,358 2.41 43,235 5/31/18
Hartford MidCap Fund 2,805,671 2.24 70,288 4/30/18
ClearBridge Aggressive Growth Fund 2,777,852 2.21 -- 12/31/17
Fidelity Select Biotechnology Portfolio 2,524,877 2.01 -- 4/30/18
Vanguard Health Care Fund 2,119,180 1.69 -- 3/31/18
Fidelity Series Growth Company Fund 2,104,782 1.68 -- 4/30/18
Vanguard Small-Cap Growth Index Fund 1,716,518 1.37 16,834 5/31/18

* Insider values reflect direct beneficial ownership.

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